The linkage of the Surveillance Epidemiology and End Results (SEER) nationwide cancer registry system and the Medicare Health Outcomes Survey (MHOS) created the SEER-MHOS dataset. This resource includes patient-reported outcomes and cancer registry information from a nationwide sample of individuals 65 and older enrolled in Medicare Advantage Organizations (managed care health plans): http://outcomes.cancer.gov/surveys/seer-mhos/). The MHOS is an ongoing study that has been recruiting multiple cohorts since 1998. Individuals ages 65 and over who are enrolled in participating Medicare Advantage Organizations are randomly sampled, administered the survey by mail or telephone, and then re-surveyed two-years later. Currently, the linked dataset contains ten cohorts, incepted beginning in 1998 and ending in 2009, representing over 95,000 individual participants of MHOS and diagnosed with cancer in SEER. During the years 1998-2005, the primary health-related quality of life measure of physical and emotional functioning was the Medical Outcomes Study Short Form-36 (SF-36). Beginning in 2006, with the implementation by CMS of the MHOS 2.0, the Veterans RAND 12-item Health Survey (VR-12) replaced the SF-36 for measuring the physical and mental health status of beneficiaries. Both the SF-36 and VR-12 instruments contain the following subscales: vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning, and mental health. To date, investigators who have conducted analyses on the SEER-MHOS dataset that have examined HRQOL subscales have been limited to choosing between the earlier cohorts (1998-2006) or later cohorts (2007-8) as the subscales are not equivalent. This has limited the potential to ask important health outcome questions in older cancer survivors that do not currently have sufficient statistical power. The usual methods of calculating scale scores from the VR-12 do not precisely numerically align with the corresponding scores from the SF-36. Thus, investigators who have conducted analyses on the SEER-MHOS dataset in the past that have examined HRQOL subscales have been limited to choosing between the earlier cohorts (1998-2006) or later cohorts (2007 and on) as the 8 scales are not equivalent. This limited the potential to ask important health outcome questions in older cancer survivors that do not currently have sufficient statistical power. The goal of the previous project by the Boston University Team in 2015-2016 was to develop algorithms that allow for score matching and comparability of the scales of the VR-12 to those of the SF-36 using the MHOS data and, in particular, the SEER-MHOS datasets across multiple cohorts from 1998 to 2012, cohorts 1- 12. The algorithms are complete, statistical software programs have been created and disseminated, a technical report summarizing this work has been created, and a manuscript has been submitted for peer-review publication. In developing these algorithms, two main issues were identified: 1) Differential item functioning (DIF) among survey questions that are part of the same scale, and 2) Contextual issues that may affect responses to identically-worded questions on the SF-36 and VR-12 surveys. The purpose of this contract is to conduct further psychometric work to address these two issues.